24 Month Calibrations

Tailwind Aviation provides 24 month calibrations of altimeters and transponders as defined in the Canadian Aviation Regulations. Using state of the art testing equipment we perform each task to a high degree of efficiency and in a timely manner to get you back in the air.


Frequently Asked Questions

We’ve had a few frequently asked questions regarding the 24 month calibrations and have listed them here for everyone’s information. Please feel free to contact us for pricing information by calling us at 519-694-4435 or email This email address is being protected from spambots. You need JavaScript enabled to view it..

  • 1. I don’t operate in controlled airspace so I don't need to have the 24 month transponder calibrated +

    • This is incorrect. If the equipment is installed in the aircraft it is required to be maintained to the applicable standards.
    • In the case of altimeters this is CAR 571 Appendix B. In the case of transponders this is CAR 571 Appendix F
    • The duration at which these items shall be tested is listed under CAR 625.86 which states:
    • Altimetry Devices: (a) Altimeters and other Altimetry devices installed in aircraft operating under Instrument Flight Rules, or under visual flight rules in Class B and C Airspace or Class C and D Airspace that is designated as "Transponder Airspace" shall be calibrated at intervals not exceeding 24 months, to the parameters and tolerances outlined in Appendix B of Standard 571, or to equivalent standards acceptable to the Minister.
    • Air traffic Control (ATC) transponders : ATC Transponders, including any associated altitude sensing reporting mechanisms, where installed, shall be tested every 24 months, in accordance with Appendix F of Chapter 571 of the Airworthiness Manual.
  • 2. I am a homebuilt aircraft so I don't need to have the 24 month calibration of either altimeter or transponder completed. +

    • This is incorrect. Reference CAR 625.86 Appendix C from the previous question. Any aircraft, regardless of certified or homebuilt is required to comply with the testing of the installed altimetry devices and transponders.
  • 3. I have a homebuilt aircraft with uncertified avionics (i.e. Dynon Avionics)  so I don't need the 24 month calibration. +

    • This is incorrect. In the case of ATC transponders all transponders manufactured, are done so to the applicable TSO.
    • For uncertified displays such as the Dynon Skyview the 24 month calibration requirements for the transponder and altitude display must be complied with.
  • 4. I only fly VFR so I don't need to have the 24 month transponder calibration completed. +

    • This is incorrect.
    • Reference CAR 625.86 Appendix C. The basic thought process is if its installed it needs to be calibrated at the 24 month interval.
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